/* 全局样式增强 */
body {
  transition: background-color 0.3s;
}

main {
  min-height: calc(100vh - 200px);
}

/* 卡片悬停效果 */
[style*="background: #fff"] {
  transition: transform 0.3s, box-shadow 0.3s;
}

[style*="background: #fff"]:hover {
  transform: translateY(-5px);
  box-shadow: 0 4px 16px rgba(0,0,0,0.15) !important;
}

/* 按钮样式 */
a[style*="padding: 12px 30px"] {
  transition: background 0.3s, transform 0.2s;
}

a[style*="padding: 12px 30px"]:hover {
  transform: scale(1.05);
  opacity: 0.9;
}

/* 响应式优化 */
@media (max-width: 768px) {
  [style*="font-size: 36px"] {
    font-size: 28px !important;
  }

  [style*="font-size: 32px"] {
    font-size: 24px !important;
  }

  [style*="padding: 40px"] {
    padding: 25px !important;
  }

  [style*="padding: 30px"] {
    padding: 20px !important;
  }
}

/* 返回顶部按钮 */
.back-to-top {
  position: fixed;
  bottom: 30px;
  right: 30px;
  width: 50px;
  height: 50px;
  background: #1a73e8;
  color: #fff;
  border: none;
  border-radius: 50%;
  font-size: 20px;
  cursor: pointer;
  opacity: 0;
  transition: opacity 0.3s, transform 0.3s;
  z-index: 999;
}

.back-to-top.visible {
  opacity: 1;
}

.back-to-top:hover {
  transform: translateY(-5px);
}